The present invention relates to a tapered support member for disparate articles, and a method for forming the same.
In the past, tapered, metallic support members such as sign posts, telephone poles, street lamps, and the like, have been formed by spinning a length of stock material on a lathe to a desired configuration. Such spinning operations involve an excessive waste of materials, provide a slow production rate, and are an expensive mode of manufacture. Often, the spinning milling operation results in a member having relatively thin wall construction which does not offer high strength characteristics and, as a result, alternative methods of manufacturing tapered support members have been devised.
Many of the above-noted difficulties can be overcome by forming an elongated member from a rolled or pressed piece of metal which is embraced by a plurality of metallic rings or bands for holding the rolled metal to form a tapered pole. Also, the rolled metal may be joined by a full length weld seam, which must be ground flush. Compared with the extrusion of metallic members by means of extrusion dies, however, both methods are still relatively cumbersome and costly.
Other tapered structural members are formed from a plurality of extruded metal elements having longitudinal edges connected by adhesive means. The use of adhesive to interconnect the longitudinal edges of such elements, however, gives rise to expansion and contraction problems under varying weather conditions which undermine the member's structural integrity. In addition, an extrusion die with an extremely large circumscribed-circle capability is required in order to produce the elements which make up such tapered structural members and due to characteristics of the extrusion art, the wider the section the thicker the cross section must be, thereby resulting in more material usage than normally needed for strength, thus adding to cost.
Accordingly it is an object of this invention to provide a method of making a tapered support member for disparate articles which reduces excessive waste of construction materials.
A further object is to provide a method of manufacture which allows the use of aluminum, plastics, or other suitable materials, which offer more desirable strength characteristics as well as excellent resistance to corrosion.
Yet another object of this invention is to provide a tapered structural member having desirable strength characteristics under varying weather conditions.
One of the advantages of the invention about to be described is that it provides an inexpensive method of manufacturing a tapered structural member.
Another advantage of the invention is that it permits a tapered support member to be constructed from a plurality of components that are extruded from aluminum, plastics, or other suitable materials. Similarly the invention provides a method of coupling the component parts of a tapered support member so as to reduce structural problems associated with the expansion and contraction of the member under varying weather conditions.